Package org.apache.commons.codec.language

Class Metaphone

  • All Implemented Interfaces:
    Encoder, StringEncoder
    public class Metaphone
extends java.lang.Object
implements StringEncoder
    Encodes a string into a Metaphone value.

    Initial Java implementation by William B. Brogden. December, 1997. Permission given by wbrogden for code to be used anywhere.

    Hanging on the Metaphone by Lawrence Philips in Computer Language of Dec. 1990, p 39.

    Note, that this does not match the algorithm that ships with PHP, or the algorithm found in the Perl implementations:

    They have had undocumented changes from the originally published algorithm. For more information, see CODEC-57.

    This class is conditionally thread-safe. The instance field maxCodeLen is mutable setMaxCodeLen(int) but is not volatile, and accesses are not synchronized. If an instance of the class is shared between threads, the caller needs to ensure that suitable synchronization is used to ensure safe publication of the value between threads, and must not invoke setMaxCodeLen(int) after initial setup.

    • Field Summary

      Fields 
      Modifier and Type Field Description
      private static java.lang.String FRONTV
      Variable used in Metaphone algorithm
      private int maxCodeLen
      The max code length for metaphone is 4
      private static java.lang.String VARSON
      Variable used in Metaphone algorithm
      private static java.lang.String VOWELS
      Five values in the English language

    • Constructor Summary

      Constructors 
      Constructor Description
      Metaphone()
      Creates an instance of the Metaphone encoder

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      java.lang.Object encode​(java.lang.Object obj)
      Encodes an Object using the metaphone algorithm.
      java.lang.String encode​(java.lang.String str)
      Encodes a String using the Metaphone algorithm.
      int getMaxCodeLen()
      Returns the maxCodeLen.
      private boolean isLastChar​(int wdsz, int n)  
      boolean isMetaphoneEqual​(java.lang.String str1, java.lang.String str2)
      Tests is the metaphones of two strings are identical.
      private boolean isNextChar​(java.lang.StringBuilder string, int index, char c)  
      private boolean isPreviousChar​(java.lang.StringBuilder string, int index, char c)  
      private boolean isVowel​(java.lang.StringBuilder string, int index)  
      java.lang.String metaphone​(java.lang.String txt)
      Find the metaphone value of a String.
      private boolean regionMatch​(java.lang.StringBuilder string, int index, java.lang.String test)  
      void setMaxCodeLen​(int maxCodeLen)
      Sets the maxCodeLen.

      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

    • Field Detail

      • VOWELS

        private static final java.lang.String VOWELS
        Five values in the English language
        See Also:
        Constant Field Values

      • FRONTV

        private static final java.lang.String FRONTV
        Variable used in Metaphone algorithm
        See Also:
        Constant Field Values

      • VARSON

        private static final java.lang.String VARSON
        Variable used in Metaphone algorithm
        See Also:
        Constant Field Values

      • maxCodeLen

        private int maxCodeLen
        The max code length for metaphone is 4

    • Constructor Detail

      • Metaphone

        public Metaphone()
        Creates an instance of the Metaphone encoder

    • Method Detail

      • metaphone

        public java.lang.String metaphone​(java.lang.String txt)
        Find the metaphone value of a String. This is similar to the soundex algorithm, but better at finding similar sounding words. All input is converted to upper case. Limitations: Input format is expected to be a single ASCII word with only characters in the A - Z range, no punctuation or numbers.
        Parameters:
        txt - String to find the metaphone code for
        Returns:
        A metaphone code corresponding to the String supplied

      • isVowel

        private boolean isVowel​(java.lang.StringBuilder string,
                        int index)

      • isPreviousChar

        private boolean isPreviousChar​(java.lang.StringBuilder string,
                               int index,
                               char c)

      • isNextChar

        private boolean isNextChar​(java.lang.StringBuilder string,
                           int index,
                           char c)

      • regionMatch

        private boolean regionMatch​(java.lang.StringBuilder string,
                            int index,
                            java.lang.String test)

      • isLastChar

        private boolean isLastChar​(int wdsz,
                           int n)

      • encode

        public java.lang.Object encode​(java.lang.Object obj)
                        throws EncoderException
        Encodes an Object using the metaphone algorithm. This method is provided in order to satisfy the requirements of the Encoder interface, and will throw an EncoderException if the supplied object is not of type java.lang.String.
        Specified by:
        encode in interface Encoder
        Parameters:
        obj - Object to encode
        Returns:
        An object (or type java.lang.String) containing the metaphone code which corresponds to the String supplied.
        Throws:
        EncoderException - if the parameter supplied is not of type java.lang.String

      • encode

        public java.lang.String encode​(java.lang.String str)
        Encodes a String using the Metaphone algorithm.
        Specified by:
        encode in interface StringEncoder
        Parameters:
        str - String object to encode
        Returns:
        The metaphone code corresponding to the String supplied

      • isMetaphoneEqual

        public boolean isMetaphoneEqual​(java.lang.String str1,
                                java.lang.String str2)
        Tests is the metaphones of two strings are identical.
        Parameters:
        str1 - First of two strings to compare
        str2 - Second of two strings to compare
        Returns:
        true if the metaphones of these strings are identical, false otherwise.

      • getMaxCodeLen

        public int getMaxCodeLen()
        Returns the maxCodeLen.
        Returns:
        int

      • setMaxCodeLen

        public void setMaxCodeLen​(int maxCodeLen)
        Sets the maxCodeLen.
        Parameters:
        maxCodeLen - The maxCodeLen to set